1 files changed, 46 insertions, 49 deletions

diff --git a/crypto/src/asn1/cmp/PbmParameter.cs b/crypto/src/asn1/cmp/PbmParameter.cs
index 206b89ba1..f4b702ed5 100644
--- a/crypto/src/asn1/cmp/PbmParameter.cs
+++ b/crypto/src/asn1/cmp/PbmParameter.cs
@@ -1,77 +1,74 @@
 using System;
 
 using Org.BouncyCastle.Asn1.X509;
-using Org.BouncyCastle.Utilities;
 
 namespace Org.BouncyCastle.Asn1.Cmp
 {
+    /**
+     *  PBMParameter ::= SEQUENCE {
+     *          salt                OCTET STRING,
+     *          -- note:  implementations MAY wish to limit acceptable sizes
+     *          -- of this string to values appropriate for their environment
+     *          -- in order to reduce the risk of denial-of-service attacks
+     *          owf                 AlgorithmIdentifier,
+     *          -- AlgId for a One-Way Function (SHA-1 recommended)
+     *          iterationCount      INTEGER,
+     *          -- number of times the OWF is applied
+     *          -- note:  implementations MAY wish to limit acceptable sizes
+     *          -- of this integer to values appropriate for their environment
+     *          -- in order to reduce the risk of denial-of-service attacks
+     *          mac                 AlgorithmIdentifier
+     *          -- the MAC AlgId (e.g., DES-MAC, Triple-DES-MAC [PKCS11],
+     *      }   -- or HMAC [RFC2104, RFC2202])
+     */
     public class PbmParameter
         : Asn1Encodable
     {
-        private Asn1OctetString salt;
-        private AlgorithmIdentifier owf;
-        private DerInteger iterationCount;
-        private AlgorithmIdentifier mac;
-
-        private PbmParameter(Asn1Sequence seq)
-        {
-            salt = Asn1OctetString.GetInstance(seq[0]);
-            owf = AlgorithmIdentifier.GetInstance(seq[1]);
-            iterationCount = DerInteger.GetInstance(seq[2]);
-            mac = AlgorithmIdentifier.GetInstance(seq[3]);
-        }
-
         public static PbmParameter GetInstance(object obj)
         {
-            if (obj is PbmParameter)
-                return (PbmParameter)obj;
+            if (obj is PbmParameter pbmParameter)
+                return pbmParameter;
 
-            if (obj is Asn1Sequence)
-                return new PbmParameter((Asn1Sequence)obj);
+            if (obj != null)
+                return new PbmParameter(Asn1Sequence.GetInstance(obj));
 
-            throw new ArgumentException("Invalid object: " + Platform.GetTypeName(obj), "obj");
+            return null;
         }
 
-        public PbmParameter(
-            byte[] salt,
-            AlgorithmIdentifier owf,
-            int iterationCount,
-            AlgorithmIdentifier mac)
-            : this(new DerOctetString(salt), owf, new DerInteger(iterationCount), mac)
-        {
-        }
+        private readonly Asn1OctetString m_salt;
+        private readonly AlgorithmIdentifier m_owf;
+        private readonly DerInteger m_iterationCount;
+        private readonly AlgorithmIdentifier m_mac;
 
-        public PbmParameter(
-            Asn1OctetString salt,
-            AlgorithmIdentifier owf,
-            DerInteger iterationCount,
-            AlgorithmIdentifier mac)
+        private PbmParameter(Asn1Sequence seq)
         {
-            this.salt = salt;
-            this.owf = owf;
-            this.iterationCount = iterationCount;
-            this.mac = mac;
+            m_salt = Asn1OctetString.GetInstance(seq[0]);
+            m_owf = AlgorithmIdentifier.GetInstance(seq[1]);
+            m_iterationCount = DerInteger.GetInstance(seq[2]);
+            m_mac = AlgorithmIdentifier.GetInstance(seq[3]);
         }
 
-        public virtual Asn1OctetString Salt
+        public PbmParameter(byte[] salt, AlgorithmIdentifier owf, int iterationCount, AlgorithmIdentifier mac)
+            : this(new DerOctetString(salt), owf, new DerInteger(iterationCount), mac)
         {
-            get { return salt; }
         }
 
-        public virtual AlgorithmIdentifier Owf
+        public PbmParameter(Asn1OctetString salt, AlgorithmIdentifier owf, DerInteger iterationCount,
+            AlgorithmIdentifier mac)
         {
-            get { return owf; }
+            m_salt = salt;
+            m_owf = owf;
+            m_iterationCount = iterationCount;
+            m_mac = mac;
         }
 
-        public virtual DerInteger IterationCount
-        {
-            get { return iterationCount; }
-        }
+        public virtual DerInteger IterationCount => m_iterationCount;
 
-        public virtual AlgorithmIdentifier Mac
-        {
-            get { return mac; }
-        }
+        public virtual AlgorithmIdentifier Mac => m_mac;
+
+        public virtual AlgorithmIdentifier Owf => m_owf;
+
+        public virtual Asn1OctetString Salt => m_salt;
 
         /**
          * <pre>
@@ -95,7 +92,7 @@ namespace Org.BouncyCastle.Asn1.Cmp
          */
         public override Asn1Object ToAsn1Object()
         {
-            return new DerSequence(salt, owf, iterationCount, mac);
+            return new DerSequence(m_salt, m_owf, m_iterationCount, m_mac);
         }
     }
 }